Christian Horner has ordered an internal investigation as a result of suspicions Ferrari was basing its pit stops on Red Bull's strategy at the Spanish Grand Prix.

With pit-stop strategy more crucial than ever this season, the handling of the stops has become key in deciding the outcome of races. And while Horner is not claiming anything happened which was underhand, he is aware his team needs to be more careful about the signals it gives off as they appear to have been seized on by its rival.

Horner became suspicious when it was pointed out to him that every time Mark Webber was called into the pits, Fernando Alonso, who was ahead of him, stopped at the same time. In the end, Red Bull issued a dummy call to Webber. As Alonso darted into the pits, Webber then stayed out on track, gaining fourth place from the Ferrari, a position he never relinquished.

"It wasn't coincidence," Horner said. "Every time we called Mark in, Fernando would come down the pitlane. It was obviously quite frustrating for Mark that every time he came into the box, he's got a Ferrari right ahead of him.

"I don't know whether our mechanics were putting their hands in their pockets at the wrong time or somebody was picking up a tyre in Spain. So we have just changed our procedure this weekend to be less transparent."

Teams watch each other very closely, and equally are aware they are being watched. Radio messages to drivers are encrypted, and even then some teams devise code words to further disguise their conversations.